Lith developer and "old brown" question

I made up some Moersch easylith (1:25) for my first ever lith session last week and pulled 2 prints after letting a sheet of ordinary exposed MGRC go black to "season" the developer. The used developer didn't change colour and remains looking exactly the same in the storage bottles.

Q1. can I reuse this developer again, and for how long/what capacity
Q2 I thought used lith developer was "old brown". How long does it take to go brown, or is it "old brown" even if it hasn't changed colour?